Inter-Network Change Method and Apparatus, and Related Device

Abstract

An inter-network change method and apparatus, where a terminal determines second network slice information to which first network slice information is mapped. The first network slice information is information about a first network slice accessed by the terminal, the second network slice information is information about a second network slice, the first network slice is a network slice in a first network, and the second network slice is a network slice in a second network. The terminal sends a request message to the second network and receives an accept message returned by the second network, such that the terminal accesses a network slice identified by network slice information accepted by the second network. It can be learned that embodiments of the present disclosure can implement a handover operation between network slices of different networks.

1 . A method, comprising:
 receiving, from a terminal and during a registration procedure of the terminal in a first network or after completion of the registration procedure, a packet data network (PDN) connection request requesting a PDN connection, wherein the first network is a 4th generation (4G) mobile communications system;   determining network slice information about a network slice in a second network, wherein the network slice corresponds to the PDN connection, wherein the second network is a 5th generation (5G) mobile communications system, and wherein the first network and the second network have different core network devices; and   sending, to the terminal, a PDN connection response message comprising the network slice information.   
     
     
         2 . The method of  claim 1 , wherein the network slice information comprises one or more pieces of single-network slice selection assistance information (S-NSSAI). 
     
     
         3 . The method of  claim 2 , wherein the one or more pieces of S-NSSAI comprise a slice/service type or slice differentiation information. 
     
     
         4 . The method of  claim 1 , wherein the 4G mobile communications system comprises an Evolved Packet Core (EPC) system or an Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN). 
     
     
         5 . The method of  claim 1 , further comprising:
 receiving, from the terminal, a request message carrying the network slice information for the terminal to register with or be handed over to the second network; and   sending, to the terminal, an accept message carrying allowed network slice information from the second network,   wherein the allowed network slice information comprises a part or all of the network slice information.   
     
     
         6 . The method of  claim 5 , further comprising establishing, based on the network slice information and after the terminal registers with or is handed over to the second network, a packet data unit (PDU) session with the terminal. 
     
     
         7 . The method of  claim 6 , wherein establishing the PDU session with the terminal comprises receiving, from the terminal, a session establishment request message comprising the network slice information. 
     
     
         8 . The method of  claim 6 , wherein a first Internet Protocol (IP) address of the PDU session is the same as a second IP address of the PDN connection. 
     
     
         9 . An apparatus, comprising:
 at least one memory configured to store instructions; and   at least one processor coupled to the at least one memory and configured to execute the instructions to cause the apparatus to:
 receive, from a terminal and during a registration procedure of the terminal in a first network or after completion of the registration procedure, a packet data network (PDN) connection request requesting a PDN connection, wherein the first network is a 4th generation (4G) mobile communications system; 
 determine network slice information about a network slice in a second network, wherein the network slice corresponds to the PDN connection, wherein the second network is a 5th generation (5G) mobile communications system, and wherein the first network and the second network have different core network devices; and 
 send, to the terminal, a PDN connection response message comprising the network slice information. 
   
     
     
         10 . The apparatus of  claim 9 , wherein the network slice information comprises one or more pieces of single-network slice selection assistance information (S-NSSAI). 
     
     
         11 . The apparatus of  claim 10 , wherein the one or more pieces of S-NSSAI comprise a slice/service type or slice differentiation information. 
     
     
         12 . The apparatus of  claim 9 , wherein the 4G mobile communications system comprises an Evolved Packet Core (EPC) system or an Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN). 
     
     
         13 . An apparatus, comprising:
 at least one memory configured to store instructions; and   at least one processor coupled to the at least one memory and configured to execute the instructions to cause the apparatus to:
 receive, from a terminal, a request message carrying network slice information for the terminal to register with or be handed over to a second network, wherein the network slice information is about a network slice in the second network, wherein the network slice corresponds to a packet data network (PDN) connection of the terminal in a first network, wherein the first network is a 4th generation (4G) mobile communications system, wherein the second network is a 5th generation (5G) mobile communications system, and wherein the first network and the second network have different core network devices; and 
 send, to the terminal, an accept message carrying allowed network slice information from the second network, 
 wherein the allowed network slice information comprises a part or all of the network slice information. 
   
     
     
         14 . The apparatus of  claim 13 , wherein the at least one processor is further configured to execute the instructions to cause the apparatus to establish, based on the network slice information and after the terminal registers with or is handed over to the second network, a packet data unit (PDU) session with the terminal. 
     
     
         15 . The apparatus of  claim 14 , wherein the at least one processor is further configured to execute the instructions to cause the apparatus to receive, from the terminal, a session establishment request message comprising the network slice information. 
     
     
         16 . The apparatus of  claim 14 , wherein a first Internet Protocol (IP) address of the PDU session is the same as a second IP address of the PDN connection. 
     
     
         17 . The apparatus of  claim 13 , wherein the network slice information comprises one or more pieces of single-network slice selection assistance information (S-NSSAI). 
     
     
         18 . The apparatus of  claim 17 , wherein the one or more pieces of S-NSSAI comprise a slice/service type or slice differentiation information. 
     
     
         19 . The apparatus of  claim 13 , wherein the 4G mobile communications system comprises an evolved packet core (EPC) system or an evolved universal mobile telecommunications system (UMTS) terrestrial radio access network (E-UTRAN). 
     
     
         20 . A system, comprising:
 a first apparatus in a first network, wherein the first network is a 4th generation (4G) mobile communications system, and wherein the first apparatus is configured to:
 receive, from a terminal and during a registration procedure of the terminal in the first network or after completion of the registration procedure, a packet data network (PDN) connection request requesting a PDN connection; 
 determine network slice information about a network slice in a second network, wherein the network slice corresponds to the PDN connection, wherein the second network is a 5th generation (5G) mobile communications system, and wherein the first network and the second network have different core network devices; and 
 send, to the terminal, a PDN connection response message comprising the network slice information; and 
   a second apparatus in the second network and configured to:
 receive, from the terminal, a request message carrying the network slice information for the terminal to register with or be handed over to the second network; and 
 send, to the terminal, an accept message carrying allowed network slice information from the second network, 
 wherein the allowed network slice information comprises a part or all of the network slice information.